The Bridge Area Of ​​the Nujiang Leap Recovery Alternatives Study, Upon Mechanism Analysis And Leap Bridge Springs

Yuejin Bridge Hot Spring is located at the place which is 200m away from the lower dam site of the Nujiang Lushui hydropower station. All the local ethnic groups hold the "bathhouse gathering" in the first lunar month every year and the construction of the hydropower station will submerge the hot springs. In order to preserve these unique attractions of humanities and history, it is necessary to do researches on the submerging influence of the reservoir backwater on the hot springs and on the restoration and alternative programs.The study area belongs to the southern part of traverse Mountains in western Yunnan and in general, the topography is of such features as the northern part is high and the southern part is low. The main mountain range and the water are of north-south extended and the main landscape types are the Nujiang deep canyon topography and the seasonal river erosion landform. The first class geotectonic unit is the fold line of Gangdise-Nyainqentanglha (V) and the secondary unit is Fugong-Zhenkang Fold Belt (V2) which is closed to Boshula Ridge-Gaoligongshan-Qamdo-Lanping-Simao fold. Paleozoic and Mesozoic strata, regional folds, and fracture development are widely distributed here; the structural features are mainly with fractures; the main tectonic line is of north-south extended, followed by east-west extended and north-east extended partly. The feature of the new tectonic movement is peculiar. Hydro-geological conditions are simple.The study area exposes three hot spring clusters, namely, Yuejin Bridge Hot Springs, Mabu River Hot Springs and Dishuihe Hot Springs. This paper analyzes their exposing characteristics, geological features and chemical characteristics of the water.Yuejin Bridge Hot Springs have 8 sites of exposing springs. The topographic type of the exposing area is the Nujiang deep canyon topography and the stratigraphyies are the Upper Carbonic Lying Cattle Team (C3W) and the the Upper Section of Triassic River Bend Team (T2h1). Every spring point exposes along with the water faultage Fl.The spring water is warm; the chemical type of the water contains HCO3-Ca2+ type; the supply source for the hot spring is the meteoric water with 2050m recharge height; the thermal energy storage temperature is 82.8℃calculated by SiO2 standard method; the estimated depth of water cycle is 1814m and type of the cause is the deep infiltration cycle hot spring. Mabu River Hot Springs have 2 sites of exposing springs. The topographic type of the exposing area is the Nujiang deep canyon topography and the stratigraphies are the Upper Carbonic Lying Cattle Team (C3w) and the the Upper Section of Triassic River Bend Team (T2h1). Every spring point exposes along with the water faultage F. The spring water is warm water and hot water; the chemical type of the water is HCO3--Ca2+·Na+ type; the supply source for the hot spring is the meteoric water with 2210m recharge height; the thermal energy storage temperature is 100℃calculated by K-Mg standard method; the estimated depth of water cycle is 2637m and the type of the cause is the deep infiltration cycle rising hot spring.The spring sites of the Dishui River hot springs disperse on the river bed and river floodplain of the Dishui River. The topographic type of the exposing area is river erosion landform and the stratigraphy of the exposing area is the early Yanshan granite and every spring point exposes along with the water faultage. The spring water is hot water; the chemical type of the water is HCO3-Ca2+·Na+type; the supply source for the hot spring is the meteoric water with 2180m recharge height; the thermal energy storage temperature is 100.4℃calculated by Na-K standard method; the estimated depth of water cycle is 1230m and the type of the cause is the remnants of hot water rising hot spring after the magma period.In the course of the study, chemical type of the hot spring water is compared with that of the surface water to determine that the chemical type of Nujiang water is HCO3-·SO42--Mg2+type; the chemical type of the Dishui River is HCO3--Ca2+·Na+type and in the same time comparative analysis of trace elements is also conducted.By analyzing the submerging influence mechanism of the reservoir backwater on Yuejin Bridge Hot Spring, the Yuejin Bridge Hot Springs water drainage program, Mabu River Hot Springs exploitation program and Dishui River Hot Springs water drainage program are compared with one another from the perspectives of hot spring water quality, water yield, the conditions of traffic location and the conditions of human geography to finalize the program of the Dishui River Hot Springs replacing Yuejin River Bridge Hot Springs.